package net.kesumu.general.java;

public class StringOperation {

    public StringOperation() {
    }
    
    public static boolean isPositiveInteger(String s) {
        if(s == null || s == "") {
            return false;
        }
        char letter;
        for(int i=0;i<s.length();i++) {
            letter = s.charAt(i);
            if(letter < '0' || letter > '9') {
                return false;
            }
        }
        return true;
    }

}
